7
Where:
D
=
Max.
cable
length
in
feet.
V
S
=
Power
supply
voltage.
R
=
Cable
resistance
in
ohms
per
1000
feet.
Example:
VS
=
24
Volts
R
=
16.1
(22
AWG
cable)
𝐷
24
10
4
∗
10
16.1
21,739
𝐹𝑒𝑒𝑡
d.
HART
Connection
for
a
Safe
Area
Installation
Metal
Samples
MS2901E
supports
HART
communication
protocol.
HART
is
an
acronym
for
Highway
Addressable
Remote
Transducer.
The
HART
protocol
makes
use
of
the
Bell
202
FSK
standard
to
superimpose
digital
signals
at
a
low
level
on
top
of
the
4
‐
20
mA
Signal.
This
enables
two
‐
way
communication
and
makes
it
possible
for
additional
information
beyond
just
the
normal
process
variable
to
be
communicated
to
and
from
a
field
instrument.
MS2901E
can
be
connected
to
HART
modem
to
communicate
with
the
computer
in
a
safe
area.
Connect
the
modem
across
250
Ohms
resistor
in
line
with
current
loop
supply
as
shown
in
figure.
Any
certified
handheld
terminal
can
be
connected
to
the
current
loop
supply
of
the
instrument
to
communicate
and
access
the
variables
and
the
probe
life
and
other
items
can
be
set
from
remote
terminal.
(Refer
Handheld
equipment’s
connection
details
for
proper
connection
details).
Due
to
the
sensitive
nature
of
corrosion
measurement,
it
is
important
to
provide
good
electrical
isolation
between
the
I/O
system/power
supply
and
each
4
‐
20
mA/HART
signal
from
MS2901E.
Metal
Samples
recommends
using
isolator
or
isolated
I/o
card
to
connect
to
the
PLC
/DCS
HART
connections
For
all
other
general
applications,
a
signal
conditioner
capable
of
repeating
the
4
‐
20
mA/HART
signals
and
providing
at
least
500
V
of
isolation
must
be
used.
If
you
are
using
Summary of Contents for MS2901E
Page 2: ......
Page 4: ......
Page 45: ...41 Appendix B Hazardous Area Certification Details...
Page 46: ...42...
Page 47: ...43...
Page 48: ...44...
Page 49: ...45...
Page 50: ...46...
Page 51: ...47...
Page 52: ...48 Appendix C Drawings A Wiring Diagrams Control Drawing Hazardous Area Wiring Diagram...
